Armrest height-adjusting device

ABSTRACT

An armrest height-adjusting device has a collar ( 10 ) fixed to an arm frame ( 8 ) and a spring ( 11 ). The spring ( 11 ) includes a coil portion ( 11 A), provided around the collar ( 10 ), a first leg portion ( 11 B) engaging with the seat back frame ( 5 ), and a second leg portion ( 11 C) received in a window portion ( 41 ) of the arm frame ( 8 ). A diameter of the coil portion ( 11 A) becomes short by the downward rotation of the arm frame ( 8 ) and becomes large by the upward rotation of the arm frame ( 8 ). The second leg portion ( 11 C) is guided into the hook ( 24 ) by abutting against the window portion ( 41 ) when the arm frame ( 10 ) is rotated upward beyond a predetermined position. When the second leg portion ( 11 C) is engaged with the hook ( 24 ), the diameter of the coil portion ( 11 A) is kept in a state of becoming large.

TECHNICAL FIELD

The present invention relates to an armrest height-adjusting device of avehicle seat.

BACKGROUND ART

Heretofore, in general, a height-adjusting device having a lock springand a shaft disposed within a coil portion of the lock spring andholding an armrest at an arbitrary position by frictional resistancegenerated between the coil portion and the shaft has been publicly known(for example, Japanese Utility Model Application Laid-Open No. 5-53547).

The prior art device has been carrying a problem of requiring anoperating lever to increase and decrease the frictional resistancebetween the coil portion and the shaft.

Further, the prior art device has caused trouble in the positionadjustment method of the armrest.

DISCLOSURE OF THE INVENTION

An object of the present invention is to provide an armrestheight-adjusting device, which does not require an operating lever.

Further, another object of the present invention is to provide anarmrest height-adjusting device, which is simple in an operation method.

Further, another object of the present invention is to provide anarmrest height-adjusting device, which can simply change a working rangeof the armrest.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a vehicle seat comprising an armrestheight-adjusting device according to the present invention;

FIG. 2 is an exploded oblique view of a lock device of theheight-adjusting device;

FIG. 3 is an oblique view of the lock device;

FIG. 4 is a side view showing a seat back frame and the armrest frame ata lower limit position;

FIG. 5 is an oblique view of the lock device when the armrest is at thelower limit position;

FIG. 6 is an oblique view of the lock device when the armrest is at thetop position in a working range;

FIGS. 7 and 8 are oblique views of the lock device when the armrestmoves from the working range to a storing range;

FIG. 9 is an oblique view of the lock device when the movement to thestoring range of the armrest is completed;

FIG. 10 is an oblique view of the lock device when the armrest is at anupper limit position;

FIG. 11 is an oblique view of the lock device when the armrest moves tothe vicinity of the lower limit position from the storage position; and

FIG. 12 is a view showing a relation between a window portion of aspring cover and a hook of a bent plate.

BEST MODE FOR CARRYING OUT THE INVENTION

An embodiment of the present invention will be described with referenceto the drawings. A vehicle seat 1 according to the present invention hasa seat bottom 2 slidably attached to a vehicle body (not shown), areclining seat back 3 rotatably supported by the seat bottom 2, and anarmrest 4 provided at the side portion of the seat back 3.

A seat back frame 5 of the seat back 3 is fixed with a bracket 6. An armframe 8 of the armrest 4 is rotatably attached to the bracket 6 (frame8) by a shaft 7 extending in a left-and-right direction of the vehicleseat. Between a base of the arm frame 8 and the seat back frame 5, alock device 40 is provided.

The armrest 4, as shown in FIG. 1, is displaceable between a lower limitposition L and an upper limit position H. The armrest 4 is usually usedwithin a working range A. In the working range A, the armrest 4 is heldat an arbitrary position by the lock device 40. That is, thedisplacement of the armrest 4 toward the lower limit position L isrestricted by the lock device 40. However, the lock device 40 does notrestrict the displacement of the armrest 4 toward the upper limitposition H. Further, the lock device 40 does not restrict the rotationof the armrest 4 in a storing range B set upward than the working rangeA. That is, the armrest 4 freely rotates in the storing range B.Further, the lock device 40 does not restrict the rotation of thearmrest 4 in the working range A when the armrest 4 is displaced fromthe storing range B into the working range A. A locking function of thelock device 40 in the working area A is restored when the armrest 4 issubstantially displaced till the lower limit position L.

The lock device 40 has a lock spring 11. A coil portion 11A of a spring11 is disposed on the outer periphery of a collar 10, and the shaft 7 isinserted into the collar 10. One end of the collar 10 penetrates throughthe bracket 6 so as to be fixed to the arm frame 8. Consequently, thecollar 10 rotates integrally with the armrest 4. A first bent legportion 11B of the lock spring 11 is engaged with an engaging hole 14 ofa secondary bracket 13 which is fixed to the bracket 6. A secondstraight leg portion 11C is allowed to protrude long in the radialdirection of the coil portion 11A. The coil portion 11A closely contactsthe collar 10 with adequate strength.

The other end of the collar 10 is fixed with a spring cover 30. Thespring cover 30 comprises a disk plate 31 and a bent flange 38 extendingfrom the outer peripheral edge of the plate 31 toward the arm frame 8.The bent flange 38 has a window portion 41 in which the second straightleg portion 11C is stored. One side surface of the window portion 41 isformed with an unlock abutting wall 32 approximately in parallel withthe axial direction of the shaft 7, and the other side surface is formedwith a return inclined wall 39.

As shown in FIG. 4, when the arm frame 8 is at the lower limit positionL, as shown in FIG. 5, the straight leg portion 11C is positioned at aterminal portion 37 of the inclined wall 39, and when the arm frame 8moves to the top position in the working range A, as shown in FIG. 6,the unlock abutting wall 32 just abuts against the straight leg portion11C. Consequently, when the arm frame 8 is positioned in the workingrange A, the spring cover 30 does not substantially abut against thestraight leg portion 11C, and the straight leg portion 11C is kept in astate in which whatever external force is not received.

When the straight leg portion 11C is in a state in which whateverexternal force is not received, the coil portion 11A closely contactsthe collar 10 with adequate strength. By the frictional resistance dueto this contact, the armrest 4 is kept at an arbitrary position in theworking range A. When the elbow of a driver and the like is mounted onthe armrest 4 and the armrest 4 (collar 10) is intended to rotatedownward, the coil portion 11A becomes short in diameter and stronglywounds around the collar 10, so that the frictional resistance betweenthe coil portion 11A and the collar 10 is instantaneously increased.This increased frictional resistance prevents the downward rotation ofthe armrest 4. When the armrest 4 is rotated upward, the diameter of thecoil 11A instantaneously becomes large, and the frictional resistancebetween the coil portion 11A and the collar 10 is reduced, so that thearmrest 4 can be smoothly rotated upward, and when rotation of thearmrest 4 is stopped, the coil portion 11A closely contacts the collar10 again with adequate strength.

The secondary bracket 13 has a bent plate 25 which is in parallel withthe shaft center of the shaft 7 and extends toward the seat back frame5, and the bent plate 25 is formed with a hook 24 capable of engagingwith the straight leg portion 11C. The hook 24 has an inclined guide camsurface 23 which guides the straight leg portion 11C into the hook 24and an unlock holding surface 22 for holding the straight leg portion11C at an unlock position. The unlock holding surface 22 is eitherformed in parallel with the shaft center of the shaft 7 or formed in agentle inclined surface as shown in FIG. 12.

Between the guide cam surface 23 and the unlock holding surface 22,there is formed a passage 26. The bent plate 25 comprises an inclinedsurface 27 communicating with the passage 26.

The end edge of the unlock abutting wall 32 of the spring cover 30, asshown in FIG. 12, is either brought into line with the end edge of theunlock holding surface 22 or these end edges are overlapped with eachother. When the armrest 4 further rotates upward from the state of FIG.6 in which the arm frame 8 is at the top position in the working rangeA, as shown in FIG. 7, the straight leg portion 11C pushed by the unlockabutting wall 32 abuts against the guide cam surface 23, and is guidedinto the hook 24. As shown in FIG. 8, when the straight leg portion 11Cmoves into the, hook 24, it falls off from the unlock abutting wall 32,and after that, the straight leg portion 11C, as shown in FIG. 9, abutsagainst the unlock holding surface 22 by the elastic force of the coilportion 11A.

As shown in FIG. 9, the position in which the straight leg portion 11Cabuts against the unlock holding surface 22 of the secondary bracket 13becomes the lower position of the storing range B of the armrest 4.

As shown in FIG. 3, the bent flange 38 is formed with a closed wall 33orthogonal to the axial direction of the shaft 7. The closed wall 33communicates with the end edge of the unlock abutting wall 32. As shownin FIG. 9, in a state in which the straight leg portion 11C abutsagainst the unlock holding surface 22, the closed wall 33 substantiallycloses the passage 26 of the hook 24, and prevents the straight legportion 11C from falling off from the unlock holding surface 22.

In a state in which the straight leg portion 11C is engaged with theunlock holding surface 22, the diameter of the coil portion 11A is keptin a state of becoming large. The frictional resistance at this timebetween the coil portion 11A and the collar 10 becomes considerablysmall, and the armrest 4 can be rotated by a slight operational force.FIG. 10 shows a state when the armrest 4 is moved till the upper limitposition H.

The end portion of the closed wall 33 is provided with a stopper 34 inparallel with the axial center of the shaft 7. The stopper 34 preventsan excessive rotation of the armrest 4.

When the armrest 4 in the storing range B is rotated downward, first,the closed wall 33 is separated from the passage 26 of the hook 24.However, usually, even if the closed wall 33 is separated from thepassage 26, the straight leg portion 11C is kept in a state engaged withthe unlock holding surface 22. The inclined unlock holding surface 22more effectively prevents the falling off of the straight leg portion11C from the unlock holding surface 22. Hence, even after the armrest 4enters the working range A, it can further move downward by a slightoperational force. When the armrest 4 comes near to the lower limitposition L, as shown in FIG. 11, the return inclined wall 39 of thespring cover 30 abuts against the straight leg portion 11C, and thisallows the straight leg portion 11C to be pushed toward the passage 26and separated from the unlock holding surface 22. Then, the straight legportion 11C is restored to the initial position by the elastic force ofthe coil portion 11A, and the frictional resistance between the coilportion 11A and the collar 10 is also restored to the adequate strength,and this allows the locking function in the working range A of the lockdevice 40 to be recovered.

EFFECT OF THE INVENTION

In the present invention, the structure is simple since the armrest 4functions as an operating lever.

In the present invention, the width of the working range A of thearmrest 4 can be simply changed through the change of the distancebetween the unlock abutting wall 32 of the spring cover 30 and theinclined wall 39 (terminal portion 37).

In the present invention, when the armrest 4 is displaced from thestoring range B toward the working range A, the closed wall 33 of thewindow portion 41 closes the passage 26 of the hook 24 so as to preventthe straight leg portion 11C from falling off from the hook 24. Hence,when the armrest 4 is displaced from the storing range B toward theworking range A, the armrest 4 can be smoothly displaced till the lowerlimit position L of the working range A.

1. An armrest height-adjusting device of a vehicle seat having a seatbottom and a seat back rotatably attached to the seat bottom,comprising: a collar provided between an arm frame of the armrest and aseat back frame of the seat back and integrally rotating with the armframe; a spring cover integrally rotating with the collar; a lock springhaving a coil portion disposed around the collar, a first leg portionengaging with the seat back frame, and a second leg portion stored intoa window portion of the spring cover; and a stationary plate fixed tothe seat back frame and having a hook capable of engaging with thesecond leg portion; wherein the coil portion, in a state in which thesecond leg portion does not receive an external force, closely contactsthe collar with adequate strength so as to generate an ordinaryfrictional resistance between the coil portion and the collar; wherein,when the armrest is rotated downward, a diameter of the coil portionbecomes short by the ordinary frictional resistance so as to increasethe frictional resistance between the coil portion and the collar;wherein, when the armrest is rotated upward, the diameter of the coilportion becomes large by the ordinary frictional resistance so as toreduce the frictional resistance between the coil portion and thecollar; wherein, the window portion has an unlock abutting wall forabutting against the second leg portion so as to guide the second legportion into the hook when the armrest is rotated upward beyond apredetermined position; wherein, the window portion further has a returninclined wall for abutting against the second leg portion so as toreturn the second leg portion to the inside of the window from the hookwhen the armrest is rotated downward in a state in which the second legportion engages with the hook; wherein the frictional resistance betweenthe coil portion and the collar, in a state in which the second legportion engages with the hook, is kept in a weaker state than theordinary frictional resistance.
 2. The armrest height-adjusting deviceaccording to claim 1, wherein the hook has an inclined guide cam surfaceto guide the second leg portion into the hook when the second legportion is displaced by abutment with the unlock abutting wall.
 3. Anarmrest height-adjusting device of a vehicle seat having a seat bottomand a seat back rotatably attached to the seat bottom, comprising: acollar provided between an arm frame of the armrest and a seat backframe of the seat back and integrally rotating with the arm frame; aspring cover integrally rotating with the collar; a lock spring having acoil portion disposed around the collar, a first leg portion engagingwith the seat back frame, and a second leg portion stored into a windowportion of the spring cover; and a stationary plate fixed to the seatback frame and having a hook capable of engaging with the second legportion; wherein the coil portion, in a state in which the second legportion does not receive an external force, closely contacts the collarwith adequate strength so as to generate an ordinary frictionalresistance between the coil portion and the collar; wherein, when thearmrest is rotated downward, a diameter of the coil portion becomesshort by the ordinary frictional resistance so as to increase thefrictional resistance between the coil portion and the collar; wherein,when the armrest is rotated upward, the diameter of the coil portionbecomes large by the ordinary frictional resistance so as to reduce thefrictional resistance between the coil portion and the collar; wherein,the window portion has an unlock abutting wall for abutting against thesecond leg portion so as to guide the second leg portion into the hookwhen the armrest is rotated upward beyond a predetermined position;wherein, the window portion further has a return inclined wall forabutting against the second leg portion so as to return the second legportion to the inside of the window from the hook when the armrest isrotated downward in a state in which the second leg portion engages withthe hook; wherein the frictional resistance between the coil portion andthe collar, in a state in which the second leg portion engages with thehook, is kept in a weaker state than the ordinary frictional resistance;wherein the spring cover has a closed wall to prevent the second legportion guided into the hook from falling off from the hook.
 4. Thearmrest height-adjusting device according to claim 2, wherein the springcover has a closed wall to prevent the second leg portion guided intothe hook from falling off from the hook.